Blood plasma and urinary biomarkers of oxidative stress in cats with urethral obstruction

BACKGROUND

This study aimed to investigate variations of the oxidative status in cats affected by urethral obstruction (UO) under Feline Idiopathic Cystitis (FIC) and Bacterial Cystitis (BC), in comparison with a group of healthy subjects. In both groups, the levels of several markers (either direct or indirect) indicative of the oxidative attack and of the antioxidant response were analyzed on plasma and urine samples. In particular, the plasma samples were evaluated for nitric oxide (NO), hydroperoxides derived by reactive oxygen activity (d-ROMs test), superoxide anion (O2-), glutathione peroxidase activity (GPx), superoxide dismutase activity (SOD), and ferric reducing antioxidant power (FRAP test); while on urine the levels of NO, d-ROMs, FRAP, SOD, malondialdehyde (MDA) and 8-hydroxydeoxyguanosine (8-OHdG) were measured. Urine of UO patients was also subjected to urine-culture test.

RESULTS

The analytical data on plasma showed that UO, independently of the FIC or BC etiology, induced the insurgence of oxidative stress conditions at the systemic level. In the urine of the UO patients, except for SOD that increased, the markers of redox status were markedly decreased due probably their compromised filtration, thus suggesting involvement of renal function (assessed also by the high levels of plasma creatinine and proteinuria) with no oxidative damage of the lower urinary tract. Moreover, the adoption of a novel oxidative stress index' (OSI) allowed to establish, by means of a numerical value, the different degrees of oxidative stress conditions for single UO patients, both in terms of oxidative attack and antioxidant response.

CONCLUSIONS

Feline urethral obstruction, induced by Idiopathic Cystitis and Bacterial Cystitis, causes oxidative stress conditions at the systemic level that do not interest the lower urinary tract. Despite to the high variability of the profiles of oxidative stress indexes both in healthy and UO patients, the determination of OSI made possible the evaluation of their single degrees of oxidative stress. Possibly the results of this investigation can be compared with those of correspondent pathologies both in humans and in other animal species.

The influence of emotional stress on Doppler-derived aortic peak velocity in boxer dogs

Background

Subaortic stenosis (SAS) is a common congenital heart disease in Boxers. Doppler‐derived aortic peak velocity (AoPV) is a diagnostic criterion for the disease.

Objectives

To investigate the influence of emotional stress during echocardiographic examination on AoPV in normal and SAS‐affected Boxers. To evaluate the effects of aortic root diameters on AoPV in normal Boxers.

Dogs

Two hundred and fifteen normal and 19 SAS‐affected Boxers.

Methods

The AoPV was recorded at the beginning of echocardiographic examination (T0), and when the emotional stress of the dog was assumed to decrease based on behavioral parameters and heart rate (T1). AoPV0–AoPV1 was calculated. In normal dogs, stroke volume index was calculated at T0 and T1. Aortic root diameters were measured and their relationship with AoPV and AoPV0–AoPV1 was evaluated.

Results

In normal dogs, AoPV was higher at T0 (median, 1.95 m/s; range, 1.60–2.50 m/s) than at T1 (median, 1.76 m/s; range, 1.40–2.20 m/s; P < .0001; reduction 9.2%). The stroke volume index at T0 also was greater than at T1 (P < .0001). Weak negative correlations were detected between aortic root size and aortic velocities. In SAS‐affected dogs, AoPV0 was higher than AoPV1 (P < .0001; reduction 7.3%).

Conclusion and Clinical Importance

Aortic peak velocity was affected by emotional stress during echocardiographic examination both in SAS‐affected and normal Boxers. In normal Boxers, aortic root size weakly affected AoPVs, but did not affect AoPV0–AoPV1. Stroke volume seems to play a major role in stress‐related AoPV increases in normal Boxers. Emotional stress should be taken into account when screening for SAS in the Boxer breed.